Mobile wireless communication devices, such as a cellular telephone or a wireless personal digital assistant, can provide a wide variety of communication services including, for example, voice communication, text messaging, internet browsing, and electronic mail. Mobile wireless communication devices can operate in a wireless communication network of overlapping “cells”, each cell providing a geographic area of wireless signal coverage that extends from a radio network subsystem (RNS) located in the cell. The radio network subsystem can include a base transceiver station (BTS) in a Global System for Communications (GSM) network or a Node B in a Universal Mobile Telecommunications System (UMTS) network. Whether idle or actively connected, a mobile wireless communication device can be associated with a “serving” cell in a wireless communication network and be aware of neighbor cells to which the mobile wireless communication device can also associate.
Mobile wireless communication devices can support both voice and data connections, in some cases simultaneously, through radio resources allocated by the radio network subsystem for a radio access portion of the wireless communication network. The voice and data connections can also include paths through circuit switched and/or packet switched domains of a core network that interconnects the mobile wireless communication device to a public switched telephone network (PSTN) and/or a public data network (PDN). In order for the data connection to route packets, also known as protocol data units (PDUs), between the mobile wireless communication device and the packet data network, a packet data protocol (PDP) context can be activated. As several different network elements can be involved in activating the PDP context and because establishing the PDP context can require a user discernable amount of time, it can be preferable to maintain the PDP context even after the data connection becomes idle when there are no data packets to transmit. Radio resources in the radio access network, however, can be scarce, and the wireless communication network can release the radio resources allocated for the data connection during an idle period while maintaining the PDP context, thus placing the data connection in a preservation mode. When new data packets arrive at the mobile wireless communication device for transmission to the public data network, new radio resources can then be allocated by the radio network subsystem over which to transport the new data packets.
During periods with high communication traffic in the radio access network, the radio network subsystem can choose to not allocate new radio resources to the mobile wireless communication device required for the data connection. In this situation, the PDP context can remain active, while the underlying data connection to support transport of the packets can be unavailable. The mobile wireless communication device can then accumulate unsent data packets in a pending data buffer and repeatedly submit service requests for radio resources until the radio resources are allocated by the radio network subsystem. These repeated service requests can add unnecessary levels of signaling traffic to an already overloaded radio access network.
Thus there exists a need to modify radio resource signaling between the mobile wireless communication device and the radio network subsystems of the wireless communication network during periods of radio access network congestion.